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Astronomers discover planet that could support life

Michelle Fay

Kepler-186f: A NASA artist's concept of the first validated Earth-size planet to orbit a distant star in the habitable zone. Photo: Reuters

Astronomers have discovered a distant planet that appears to have an atmosphere similar to Earth, the possibility of water at its surface and the theoretical potential to support life.

It is the first validated planet found in the ‘‘habitable zone’’, defined by the distance from a star that might allow for the existence of liquid water. The planet is orbiting Kepler-186, a dwarf star that’s cooler than Earth’s sun and burns hydrogen, according to a report in the journal Science. Life is most likely to arise on planets with liquid water.

‘‘The host star, Kepler 186, is an M1-type dwarf star, which means it will burn hydrogen forever,’’ said Justin Crepp, an astrophysicist from the University of Notre Dame who worked on the mission. ‘‘There is ample opportunity to develop life around this particular star and because it has just the right orbital period, water may exist in a liquid phase.’’

The planet was found using the Kepler Space Telescope and confirmed by ruling out other possibilities for what astronomers were seeing with the Gemini North and Keck II telescopes, both located on Hawaii’s Mauna Kea, according to Steve Howell, Kepler’s project scientists and a report author.

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‘‘These Earth-sized planets are extremely hard to detect and confirm, and now that we’ve found one, we want to search for more,’’ said Elisa Quintana, a report author from the NASA Ames Research Centre.

The five planet system is about 500 light-years from Earth and is found in the constellation Cygnus. The planet in the habitable zone is about 650 million kilometres from its host star, roughly the distance of Jupiter from the sun in our solar system. The other four planets are closer to their host star and are exceedingly hot, according to the astronomers.

The Kepler Space Telescope continuously measures the brightness of more than 150,000 stars. Rather than trying to ‘‘see’’ planets directly, it uncovers their existence by measuring the amount of light blocked when an object passes in front of one of the suns it is monitoring.